The in-house research effort at ING comprises 1 full-time equivalent (FTE)
from its recurrent operational budget, an additional 2 FTEs contributed by
PPARC. This effort is distributed amongst 9 members of the Astronomy Group
which includes the Head of Astronomy, 6 support astronomers and 2 PPARC research
fellows. In addition to these staff there is an additional research astronomer
(Dr. Evans) funded through a PPARC Postdoctoral research grant award to Dr.
During the years 2004 and 2005, ING staff's research productivity, as measured
by publication rate was maintained at its previous high level, publishing
approximately 200 papers in various scientific publications, approximately
50% of these appearing in refereed journals. A complete list of these papers
is included in Appendix F. As in previous years, an important aspect of the
research effort is that ING staff continue to be closely involved with on-going
research programmes which are heavily dependent on observations carried out
on our telescopes. An important example of this synergy is ING’s very
active role in the INT/WFC Hα survey of the north Galactic plane (the
IPHAS survey, PI: Prof. Drew), which involves 6 ING staff (Corradi, Greimel,
Lennon, Leisy, Skillen and Evans) and makes use of their expertise with the
Wide Field Camera, for the survey, and with AF2, for the spectroscopic follow-up.
An excellent example of collaboration with other facilities on the Roque de
Los Muchachos Observatory is typified by Ian Skillen’s involvement with
the SuperWASP facility, this project kicked off in 2004 and aims to carry
out an ultra-wide-angle survey of the northern sky. In addition Licandro co-ordinated
a multi-telescope monitoring campaign focused on Deep Impact, more of these
and other activites are discussed below.
Figure 54. IC1396, the Elephant Trunk Nebula, is
a giant cloud of gas and dust is illuminated by a massive central
star whose radiation is triggering star formation throughout the region.
This image was obtained as part of the IPHAS survey. Field of view
is approximately 15×20 arcmin, North to the left, East is down
Individual Research Activities
Benn investigated the properties of the most radio-luminous broad-absorption-line
(BAL) quasar known (1624+3758), discovered during his earlier INT search for
high-redshift radio quasars. The quasar is highly unusual, with prominent FeII
UV191 1787-A emission, a broad detached BAL trough, and the second-largest radio
rotation measure known. This suggests that the quasar is intrinsically unusual
(probably due to an exceptionally high accretion rate and also a high Eddington
ratio), rather than merely viewed at an unusual angle, as has often been posited
to explain the peculiar properties of BAL quasars. This work was carried out
in collaboration with Carballo and González (Santander), Holt (Sheffield),
Vigotti and Mack (Bologna), and Perley (NRAO). He also co-supervised (with Ellison,
Victoria, Canada) an investigation by Russell (1-year student at ING) into quasar
damped-Ly-α absorbers (DLAs), finding that there is an excess at low velocities
(v<6000 km s-1
) relative to the quasars, i.e. the properties of the DLAs can
be used to constrain clustering near high-redshift quasars.
In collaboration with Furness (1-year ING student), Schirmer (ING) and Sánchez
(Calar Alto), Benn obtained a sample of z~4.5 Ly-α galaxies from a deep
imaging search at the INT. This is the first stage of a search for the expected
dramatic decline in galaxy counts marking the epoch of re-ionisation.
Sánchez and Benn published an analysis of astronomical productivity by
country (a follow-up to their earlier analysis of the scientific productivities
of telescopes worldwide).
Corradi studied several aspects concerning Galactic and extragalactic planetary
nebulae (PNe). A significant result was the detection of systems of concentric
rings around the main bodies of the nebulae (previously known only in few PNe)
around a large fraction of the PNe that were properly imaged. This implies that
the mass loss modulation producing the rings in the last 10,000–20,000
years of the AGB evolution must be a rather ubiquitous phenomenon, and therefore
should be included in any physical model describing the critical mass loss that
takes place in this phase.
A thourough study of the dynamics of the multi-polar nebula Mz3 was performed,
showing an enigmatic system of 4 distinct outflows with different degrees of
collimation. At present, none of the existing theories can explain such a complex
mass loss behaviour from an evolved star.
Concerning extragalactic PNe, their search using the observation from the Local
Group Census survey was nearly completed, and follow-up spectroscopy with the
aim of determining their chemical properties was presented for the nearby spiral
galaxy M33. This extends our knowledge of the galaxy’s chemical content
at intermediate ages of its evolution.
Figure 55. The newly discovered Planetary Nebula
PN 126.62+1.32, the ‘Prince of Asturias’, is a rare quadrupolar
nebula and it was discovered using IPHAS data [ JPEG
Greimel has worked with Augusteijn (NOT) on the selection of red dwarf-white
dwarf binaries from the SDSS. He is also involved in the Hα survey of the Milky
Way (IPHAS) and its follow up observations. Together with Corradi (ING), Viironen
and Mampaso (both IAC) he participated in the compact PN search; together with
Steeghs (CfA), Drew and Unruh (both ICL) he defined the Hectospec and AF2 follow
up observations. He also defined the IPHAS variable star candidate list of which
follow up observations have started in collaboration with Robb (Victoria, Canada).
Lennon, together with Evans (postdoc) and Trundle (PhD student) completed the
most definitive study to date of massive star wind terminal velocities in the
Small Magellanic Cloud. This work was based on extensive allocations of HST/STIS
observing time, and the same data were used to present a comprehensive atlas
of ultra-violet spectra of metal-poor massive stars. The use of this atlas for
synthesizing the UV spectra of high-redshift star forming galaxies was also
a highlight of this project (in collaboration with Rix), as was its use to investigate
the nature of the super star clusters in NGC1705-1.
Trundle & Lennon published a comprehensive study of B-type supergiants in
the Small Magellanic Cloud, uncovering a serious discrepancy between observed
and theoretical mass-loss rates with important implications for our understanding
of mass-loss in luminous blue variables, and the physics of mass-loss in these
kinds of stars. They also also found very high surface nitrogen abundances in
these stars, typical enhancements being an order of magnitude higher than the
pristine SMC nitrogen abundance.
Evans published the first results of a 2dF survey of massive stars in the Small
Magellanic Cloud, this seminal paper providing a rich dataset comprising 4161
spectra, mostly of B and A giants/supergiants. He has also published several
core papers on detailed analyses of massive OB stars in the Magellanic Clouds
which were instrumental in revising their effective temperature scale. Lennon
& Evans also spent considerable time working on the ‘VLT-FLAMES Survey
of Massive Stars’, a Large VLT project which will ultimately produce,
as part of its brief, detailed analyses of approximately 1000 OB stars in the
Galaxy and the Magellanic Clouds. Evans is the lead author on the first two
consortium papers submitted to A&A, while there are several other papers
in preparation or already submitted.
Evans and Lennon also continued their involvment in large scale spectroscopic
surveys with contributions to the IPHAS follow-up spectroscopy, completing the
preliminary classification of several thousand spectra in selected IPHAS fields
(with student intern Mansura Jaigirdar), and contributed to the formulation
of a large programme aimed at surveying the Magellanic Clouds.
Rix has published a pioneering paper that promotes the use of new metallicity
indicators, based on iron absorption features, for measuring the chemical enrichment
of high redshift star-forming galaxies. This work was based mainly on theoretical
synthetic spectra, and she has now turned her attention to applying them to
observed spectra. Rix has also pursued her work on quasar absorption line systems.
In 2004 she was the co-author on a paper that quantified the possible impact
of dust from intervening galaxies on QSO absorber statistics.She is now collaborating
with Pettini (IoA) in a project to study the detailed physical and chemical
properties of a proximate damped Ly-α absorber.
In her role as ‘XOasis support’ for the ING’s OASIS instrument,
Rix is also involved in a research project with Lennon and Parker (1-year ING
student) to study the circumstellar properties of the Luminous Blue Variable
(LBV) P Cygni. This project exploits adaptive-optics 3D spectroscopic observations
from the WHT’s OASIS +NAOMI instrumentation suite.
Leisy continued his study of extragalactic planetary nebulae (PNe). He published
two articles about new PNe candidates in Local Group (LG) Galaxies and one about
the abundance determinations of 180 PNe in the LMC and SMC. A search for fainter
PNe, hopefully also very metal poor, has been started in the SMC and the bar
of LMC, as well as in other Local Group galaxies with the Local Group Census
survey (with the WFC and the ESO 2.2m WFI).
Many new candidates have been found in several galaxies, and most of them are
already spectroscopically confirmed. The main goal is to produce catalogs of
emission line objects, and then to do spectroscopic follow-up, mainly of PNe
and HII regions. The main goals are to determine abundances and to confirm membership
of some of the candidates lying very far away from their parent galaxy centers
(with high resolution spectroscopy at the WHT/AF2 for example). Four Local Group
galaxies (Sextans A and B, IC1613 and NGC3109) have also been observed with
the VLT/FORS2 and and time was awarded on Gemini North to observe some additional
These spectra are used to derive chemical abundances, both to better understand
the stellar evolution of intermediate mass stars and the chemical evolution
of galaxies in the Local Group and beyond. The very important effects of nuclear
processes at low metallicity will help to better constrain what happened during
the first stages of the formation of the first galaxies.
Licandro carried out a spectral (visible and near-infrared) survey of trans-neptunian
objects (TNOs) and related icy minor planets, and also studied the physics of
cometary comae. He was also the P.I. of the international campaign at the ORM
in support of the Deep Impact mission. Comet 9P/Tempel 1 was observed for several
months before the impact with the TNG, and during 10 days around the impact,
from July 2 to July 10, was observed simultaneously with the WHT, TNG and NOT
telescopes. Images in the visible and near-IR low and high resolution spectra
in the visible and near-IR, were obtained. The data, still under analysis, offer
a unique opportunity to study the properties of the dust ejected by the impactor
(amount of dust ejected, size distribution, etc), and to study also the gas
produced after the impact.
Figure 56. J-band image of comet Tempel 1 obtained
using LIRIS on the WHT on July 4th, 2005. The image is the division
of July 4th by July 3rd images. A clear jet structure is visible in
South-West direction (on the image, North is up, East is left). The
field of view of the image is 50×50 arseconds on sky which corresponds
to about 32,000 kilometres at the distance of the comet [ JPEG
The visible and near-IR spectra of several TNOs, Centaurs and comet nuclei were
obtained during 2004-2005. Particularly important is the discovery that the
surface of TNO 2005 FY9, the third largest known TNO, is very similar to that
of Pluto. The spectrum is dominated by the strong methane-ice absorption bands.
The observed bands are deeper than those in Pluto's spectrum, which is indicative
of a larger fraction of methane-ice and/or methane-ice with larger particle
size in the surface of this bright TNO. This study reveals that 2005 FY9 is
an excellent candidate to be the second. known TNO with a bound atmosphere (Pluto
is until now the only case of a TNO with atmosphere).
Other important results are those revealed by the study of the spectrum of TNOs
Quaoar and 2002 TX300, using scattering models. Both large TNOs present interesting
surface properties. Quaoar presents a large fraction of cristaline water-ice
on the surface, and clear indications of other volatiles, probably methane-ice.
2002 TX300 present the strongest ever observed water ice absorption bands, it
spectrum is similar to that of Charon. This is the first Charon-like TNO observed.
The spectra of all these large TNOs reveal that their study is very important
to understand the resurfacing processes that make that large TNOs exhibit fresh
volatiles in their surface.
Méndez and colleagues completed the search for the companion star to
Tycho SN 1572, which followed the publication of a paper in Nature
(P. Ruiz-Lapuente et al., 2004, Nature
The research team found a subgiant star, named as 'Tycho G', whose proper motion
was too high for its Galactic location and in the range of the expected gained
momentum at the supernova time. This and other features led the discovery team
to conclude that Tycho G was the companion star to Tycho SN at the time of the
explosion. Méndez also continued to participate in observations for and
preparation of papers by the Supernova Cosmology Project, the Physics of Type
Ia Supernova Explosions (RTN) and the European Supernova Consortium (ESC) collaborations.
He also researched the history of the ING, and participated in the organisation
of several international conferences and in public outreach activities.
Østensen is continuing his work with the ING Adaptive Optics group, where
his work has focused on characterisation of AO performance. In his research
he has continued his ongoing work on pulsations in subdwarf B-type stars, discovering
a number of new pulsators as well as several interesting short period binary
sdB+dM systems (in collaboration with Solheim, Oslo and Oreiro, IAC). In collaboration
with Telting (NOT) he has presented the first evidence of line profile variations
in an sdB star from time resolved spectroscopy. He has also undertaken a survey
of spectroscopic subdwarf B binaries with NAOMI in order to put the different
evolutionary scenarios proposed for these stars to a test.
Other projects in this field include mining the Sloan Digital Sky Survey for
spectroscopic and photometric data on new and known subdwarf stars, and spectroscopic
model fitting of sdB stars and sdB stars in binary systems (with Heber, Bamberg).
Østensen has continued to develop a complete database system for hot
subdwarf stars, bringing together results from the numerous blue star surveys
into one searchable databank that has now been released for public use. Østensen
also organized the 2nd Meeting of Hot Subwarf Stars on La Palma during 2005.
Schirmer continued his work on the selection of galaxy clusters using weak gravitational
lensing techniques. Such a mass-selected sample of galaxy clusters is of great
cosmological interest, since clusters of galaxies indicate the highest dark
matter density peaks in the Universe, and therefore retain a memory of the initial
conditions for structure formation. From a 20 square degree survey 30 candidate
galaxy clusters have been selected, and Mischa applied for multi-object spectroscopy
time for further detailedinvestigation. If confirmed, these clusters will form
the currently largest sample of mass-selected dark matter haloes. The main collaborators
in this project are Matturi (Padova), van Waerbeke (UBC Vancouver) and Schneider
(Bonn). The same survey data forms the basis of several other projects Mischa
is involved in, such as studies of the dark matter haloes of galaxies (Kleinheinrich
et al.), populations of Lyman-break galaxies at various redshifts (Hillebrandt
et al.), the galaxy dark matter bias (Simon et al.) (all University of Bonn),
or a census of tidal tails (Pohlen et al., IAC).
Within the framework of ING, Leisy and Schirmer are searching for planetary
nebulae in Local Group galaxies and beyond, significantly improving their detection
efficiency by means of sophisticated data reduction schemes. Together with Chris
and Furness he participates in the search for Lyman-break galaxies at redshifts
of 4 and beyond. Other of his projects encompass the identification of unknown
gamma-ray sources in the Galaxy (La Palombara et al., Milan), X-ray emitters
in NGC 300 (Carpano, Tübingen) and the search for the missing mass of the
Crab Supernova remnant, which has been an unsolved mystery for more than two
decades. Deep Hα images have recently been obtained by Lundqvist et al., and
first results look very promising.
Skillen in a collaboration with Pollacco and Todd (QUB), Bell (RAL) and Augusteijn
(NOT), is conducting an ongoing photometric search for eclipsing binary systems
in local group galaxies. Approximately one hundred new systems have been discovered
in each of M31, IC 1613 and NGC 6822. Selected systems will be followed up spectroscopically
to determine accurately their physical parameters and hence distances. The goal
of this project is to investigate the impact of the physical environment on
standard candles within the Local Group, and to reduce the uncertainty in the
determination of the Hubble Constant to within 5%.
The SuperWASP facility was inaugurated and fully commissioned in 2004, in collaboration
with Pollacco (QUB) and the WASP Consortium. The WASP project is an ultra-wide-angle
photometric survey with a precision of better than 1% of stars in the magnitude
range 7–13, with the primary goal of discovering exosolar planet transits.
It will also provide an unrivalled census of variable stars over the northern
sky; the resulting archive will be exploited for a variety of science goals,
ranging from the discovery of exosolar planets to aspects of stellar pulsation,
binarity and galactic structure. A programme, in collaboration with Barnes (Texas),
to determine high precision (0.4 km s-1
) radial velocity curves of galactic Cepheid
stars from echelle spectroscopy, has now been completed.
Rutten organized the 'Workshop on Adaptive-Optics Assisted Integral-Field
Spectroscopy' at the Hotel H10 Taburiente Playa in Los Cancajos on La Palma
during May 9–11 2005. Integral-field spectroscopy and Adaptive Optics
(AO) techniques are an increasingly important tool in astronomy. A number of
integral-field spectrographs are in operation around the world, and AO instruments
are proliferating and becoming a standard feature of in particular the largest
ground-based telescopes. The combination of integral-field spectrographs and
AO is still a relatively unexplored area where the potential benefits for astronomy
are huge. For that reason, a number of projects are under way or are being proposed
that will take advantage of the most recent technological developments in these
areas. The most prominent scientific prospects are expected to be in the areas
of study of the dynamics of the central regions of elliptical galaxies and active
galactic nuclei, spectroscopy of gravitationally lensed high-redshift galaxies,
star formation regions and outflow of evolved stars, and the dynamics of crowded
The advent of a new facility instrument at the 4.2m William Herschel Telescope,
the OASIS Integral Field Spectrograph, working in conjunction with the NAOMI
AO system prompted the holding of a workshop covering this area. Moreover, the
ING laser guide star facility (GLAS) which is currently under development, will
open up nearly the full sky to AO exploitation. This implies a huge new potential
for AO assisted spectroscopy to be carried out on large samples of objects,
as there no longer will be the restriction of having to have a nearby bright
The workshop focused on the scientific achievements and prospects of AO-assisted
integral field spectroscopy, promoting discussion and sharing of experiences
and ideas. The outcome prompted new collaborations and ideas for observing programmes,
while at the same time it provides the observatory with scientifically inspired
advice on how to maximally exploit the exciting possibilities of AO at the William
Herschel Telescope. The proceedings were published in Rutten, R. G. M., Benn,
C. R., Méndez, J., 2006, New Astronomy Reviews
Figure 57. Group photograph of participants to
the workshop on ‘Adaptive-Optics Integral-Field Spectroscopy’
Østensen organized the '2nd Meeting on Hot Subdwarf stars and related
objects' at the Real Club Náutico de Santa Cruz de La Palma during June
6–10 2005, a collaborative venture between the ING and NOT. Hot subdwarf
stars are extreme horizontal branch (EHB) stars and pre-white dwarf stars. The
EHB stars are core helium-burning stars with extremely thin hydrogen envelopes,
and form the majority of bright stars in surveys for extremely blue objects,
where they are classified as subdwarf-B (sdB) stars. They also appear in the
colour-magnitude diagrams of some globular clusters as an extension of the blue
tail formed by classical horizontal branch stars, though it is not clear why
some clusters show this feature and other do not. The pre-white dwarf stars
are related to the sdBs, but have exhausted their capacity to burn helium in
the core. Many of the brightest hot subdwarfs in the field are of this class,
and they are classified as sdO stars.
Hot subdwarf stars and their relatives are believed to be important contributors
to the hitherto mysterious UV upturn phenomenon in early-type galaxies; and
a comprehensive investigation on this issue is being performed by the Galaxy
Evolution Explorer (GALEX). The formation of EHB stars remains, in general,
a matter of debate. Recent results for Galactic EHB stars show that the majority
are close binary stars, so mass transfer and mass loss due to interactions between
the stars clearly play a role. EHB stars are an excellent tool for studying
evolution in close binary stars. Some EHB stars shows p-mode pulsations with
periods of a few minutes and some others show g-mode pulsations with periods
on the order of hours. Asteroseismology can be used to measure fundamental parameters
for these stars directly. Hot subdwarf stars are also a laboratory for studying
the effects of diffusion, weak stellar winds, radiative levitation and gravitational
settling. These processes are seen to affect the peculiar composition of their
atmospheres and also play a role in the driving mechanism for pulsations and,
perhaps, the subsequent evolution of the star.
The meeting was divided into sessions that covered a broad range of topics related
to the hot subdwarf stars. They were: evolutionary models and the UV-upturn
phenomenon; hot subdwarfs and hot HB stars in the field, clusters and galaxies;
atmospheric properties of hot subdwarf stars; hot subdwarfs in binary systems;
asteroseismology of sdB stars.
Eight half day sessions were completed during the meeting, with three sessions
dedicated to asteroseismology, two sessions for atmospheric properties and the
remaining topics filling one session each. 58 participants from all over the
world attended the meeting, almost half again as many as at the first meeting.
The proceedings are to be published in journal Baltic Astronomy
Figure 58. Announcing poster of the 2nd meeting
on ‘Hot Subdawrf Stars and Related Objects’ [ JPEG
Danny Lennon organized a Royal Astronomical Society Specialist Meeting 'Science
from La Palma —Looking Beyond 2009' in collaboration with Evans (ING)
and Drew (ICL). The meeting was held at Burlington House, Piccadilly, London,
on 14 October 2005. In 2009 the international agreement setting up the Roque
de los Muchachos Observatory on the island of La Palma will have been in existence
for a period of 30 years. In the near future the United Kingdom will have
to make a decision on whether or not to withdraw from that agreement and PPARC,
through its ownership of the Isaac Newton Group of Telescopes, has the responsibility
of deciding on the UK's involvement in the observatory beyond 2009. As part
of the decision making process, and in support of the UK's overall strategic
re-evaluation in astronomy, the ING was reviewed during 2005. It was therefore
thought timely to assess recent scientific achievements from the Roque de
los Muchachos, and to consider what role the observatory might have beyond
2009. The meeting was attended by approximately 100 astronomers from around
the UK, and was structured to allow two morning sessions of science talks
with contributors from various fields in astronomy. This was followed in the
afternoon by a series of strategy talks, culminating in a half-hour discussion
on the future of the ING.
Figure 59. The meeting 'Science from La Palma —Looking
Beyond 2009' was held at the lecture theatre of the Geological Society
at Burlington House, Piccadilly, London [ JPEG